Jewelry is generally worn to adorn the wearer. The annual global sales in the jewelry market are in the billions of dollars. The Gemological Institute of America has estimated that approximately 25% to 35% of diamonds have some degree of fluorescence. The perceived negative value of less bright stones has meant that jewelers have sought to hide this feature from, or deemphasize it, to customers. Stones with less brilliant grades sell at significant discounts in the trade.